http://sparrowa7io5pz6ud3ehqzosvepbxbxt2zphmkjsylp2zgxooko23pqd.onion/docs/server-performance.html
However, communication and server issues can lead to bad data, which is solved by refreshing the wallet in Sparrow (View menu).
This test measures only the time to retrieve all wallet data (transactions and blocks), since addresses are already subscribed to when a refresh takes place. All servers tested support batching of requests.